Water-based coating compositions containing epoxy resin(s) and (meth)acrylate(s), and methods of using the same

ABSTRACT

Water-based coating composition comprising: (a) from 0.5 to 90% by weight of at least one epoxy resin other than self-dispersing epoxy resins; (b) from 0.5 to 90% by weight of at least one (meth)acrylate of a polyol; (c) from 5.0 to 98.0% by weight of water; and (d) from 0.5 to 10% by weight of one or more dispersants; wherein the at least one (meth)acrylate comprises at least two (meth)acrylate groups per molecule, and wherein the Brookfield viscosity of the composition is less than 15000 mPas.

BACKGROUND OF THE INVENTION

WO-A-00/04106 describes coating systems containing water, epoxy resinand polyacrylates (“functional polyacrylate latex=true polymers”). Thesesystems are contacted with amine hardeners and cured. The coatingsobtainable in this way are said to be suitable for metal surfaces,particularly steel, and can be subsequently overcoated with bitumen.

DE-A-195 04 528 describes amine-curable compositions containing a partlyacrylated epoxy resin, i.e. a compound in which both epoxy and(meth)acrylate functionality are present in one and the same molecule.These compositions are said to be suitable for the production ofcoatings, particularly floor underlays. The acrylated resin is a partlyacylated epoxide monomer or oligomer and has a molecular weight of 150to 10,000 and contains at least one epoxide group and at least oneterminal (meth)acrylate group. The hardener is a mono-, di- orpolyamine.

U.S. Pat. No. 4,051,195 describes curable compositions containing anepoxy resin (with more than 1.2 epoxy groups per molecule) and apoly(meth)acrylate ester of a polyol, this ester containing >1 terminal(meth)acrylic acid group. The compositions are cured with aliphaticpolyamines (containing at least 3 amine H atoms per molecule). Examplesof the polyester are hexanediol diacrylate and trimethylolpropanetriacrylate. The described system is substantially water-free andsolvent-free (in the Examples, the water content according to the Tableis between 0.1 and 0.3% and the solvent content between 0.04 and 1.55%).

U.S. Pat. No. 3,383,434 describes curable compositions based ondiepoxide, unsaturated polyester and polyamine (containing 2 primaryamine groups). The composition cures at low temperatures. The amine issaid to react with the C═C double bonds of the polyester to formcrosslinked resins. The systems are said to have a short gel time andlow exothermy. The polyesters are derived from aliphatic glycols andunsaturated aliphatic dicarboxylic acids.

U.S. Pat. No. 4,524,107 describes water-based epoxy resin compositionsfor impregnating fibers. The composition is an aqueous emulsion of anepoxy resin, a hardener and an impact modifier. The impact modifiers arepolymers which are generally produced by emulsion polymerization.

BRIEF SUMMARY OF THE INVENTION

The present invention relates, in general, to water-based coatingcompositions containing curable components, to a process for theproduction of coatings and to the use of the coating compositions.

The problem addressed by the present invention was to provide curablewater-based coating compositions. These compositions would have at mosta small content of organic solvents but would preferably be free fromsuch solvents. In addition, the compositions would be distinguished bygood handling and application behavior (=incorporation in industriallyusable systems).

Coating Compositions

The present invention relates to water-based coating compositionscontaining curable components, characterized in that they consist of

-   A) 0.5 to 90% by weight epoxy resins excluding self-dispersing epoxy    resins,-   B) 0.5 to 90% by weight (meth)acrylates of a polyol,-   C) 5.0 to 98.0% by weight water,-   D) 0 or 0.1 to 3% by weight organic solvent and-   X) 0.5 to 10% by weight one or more dispersants,    with the following provisos:    -   the (meth)acrylates B) contain at least 2 reactive (meth)acrylic        groups per molecule,    -   the sum of the percentages by weight of components A), B),        C), D) and X) is 100% by weight and    -   the Brookfield viscosity of the composition (as measured at 23°        C.) is less than 15,000 mPas.

DETAILED DESCRIPTION OF THE INVENTION

Component A)

Component A) of the coating compositions according to the invention isformed by epoxy resins excluding self-dispersing epoxy resins. Thiscondition means that the epoxy resins do not lead to a dispersionspontaneously, i.e. without the addition of emulsifiers, dispersants orthe like, when water is added. Dispersions in the context of theinvention are understood to include both dispersions per se andemulsions.

In one embodiment, the epoxy resins A) are reaction products ofbisphenol A and/or bisphenol F with epichlorohydrin.

Examples of commercially available compounds A) are the productsChem-Res E 30 and Epikote 828 which can be obtained from CognisDeutschland GmbH.

In one embodiment, component A) is used in a quantity of 5 to 50% byweight and preferably in a quantity of 20 to 50% by weight.

Component B)

The compounds B) are (meth)acrylates of a polyol with the proviso thatthey must contain at least 2 reactive (meth)acrylic groups per molecule.

An acrylic group in the context of the invention is an —O—CO—CH═CH₂group while a methacrylic group is an —O—CO—C(CH₃)═CH₂ group.

The components B) may readily be obtained by completely or partlyesterifying polyols with acrylic acid and/or methacrylic acid.

In the context of the invention, polyols suitable for the production ofcomponent B) in the broadest sense are any organic compounds whichcontain at least two OH groups per molecule. The OH groups may be bothdirectly attached to an aliphatic group, as for example with alkanediols(for example glycols) or alkanetriols (for example glycerol ortrimethylolpropane), and directly attached to an aromatic group (as forexample with bisphenol A).

Suitable compounds B) are, for example, those disclosed on page 5, lines45 to 64 of DE-A-195 04 528.

The following are particularly preferred compounds B):

-   -   ethylene glycol di(meth)acrylate,    -   hexane-1,6-diol di(meth)acrylate, reaction products of acrylic        acid and/or methacrylic acid with products of the addition of 1        to 200 mol ethylene oxide and/or propylene oxide onto        hexane-1,6-diol;    -   trimethylol propane di(meth)acrylate, trimethylol propane        tri(meth)acrylate, reaction products of in all 2 to 3 mol        acrylic acid and/or methacrylic acid with products of the        addition of 1 to 200 mol ethylene oxide and/or propylene oxide        onto trimethylol propane;    -   glycerol di(meth)acrylate, glycerol tri(meth)acrylate, fatty        acid monoglyceride di(meth)acrylate, acrylated and/or        methacrylated soya oil epoxide, acrylated and/or methacrylated        linseed oil epoxide, reaction products of acrylic acid and/or        methacrylic acid with products of the addition of 1 to 200 mol        ethylene oxide and/or propylene oxide onto glycerol;    -   reaction products of acrylic acid and/or methacrylic acid with        (bisphenol A and/or bisphenol F) diglycidyl ether, reaction        products of acrylic acid and/or methacrylic acid with products        of the addition of 1 to 200 mol ethylene oxide and/or propylene        oxide onto (bisphenol A and/or bisphenol F) diglycidyl ether;    -   reaction products of acrylic acid and/or methacrylic acid with        α,ω-diols obtainable by reaction of 1 mol bisphenol A (or        bisphenol F) with 2 mols glycerol, subsequent reaction of the        OH-terminated diether obtained with 2 mols maleic, glutaric or        succinic anhydride and further reaction of the        carboxyl-terminated intermediate product obtained with 2 mols of        an aliphatic diol (preferably an OH-terminated diol).        Component C)

Component C) is water so that further special explanations are notnecessary. In one embodiment, the quantity of C) is 10 to 50% by weightand more particularly 35 to 50% by weight.

Component D)

Component D) is formed by solvents. Basically, any organic solventsknown to the relevant expert may be used. However, solvents known to theexpert on coating technology are preferably used. Examples of suitablesolvents are those from the classes of mono-, di- or polyalcohols,glycol esters, glycol ethers; aliphatic, cycloaliphatic and aromatichydrocarbons and, finally, ketones.

Component X)

Component X) is formed by dispersants. These are substances which arecapable of dispersing or emulsifying the epoxy resins A) to be used inaccordance with the invention in water.

Corresponding dispersants are known to the expert.

The dispersants X) are preferably selected from the group of anionic andnonionic surfactants.

Examples of suitable anionic dispersants X) include fatty alcoholsulfates and fatty alcohol ether sulfates.

Suitable nonionc disperants X) are, for example, fatty alcohols andproducts of the addition of in all 1 to 200 (preferably 10 to 110) molethylene oxide and/or propylene oxide onto fatty alcohols and/oralkylphenols, alkyl polyglucosides.

Production of the Coating Compositions

The coating compositions may be produced by any methods known to theexpert. In particular, the components may be successively mixed with oneanother. Equally, however, two or more components may first be preparedin advance and then contacted in that form with other components to formthe final coating composition. This particular variant applies inparticular to component C) (water). Water may be introduced into thesystem as a whole in many different ways during the production of thecoating compositions according to the invention. For example, compoundsof classes A) and/or B), particularly commercially available types, maybe used in an aqueous supply form. In other words, water may either beintroduced with the other compulsory components of the coatingcomposition or may even be introduced by using individual or allcomponents A) and/or B) in aqueous supply forms. A combination of bothmethods is also possible.

The percentages by weight for components A) and B) are always based onthe particular active substance content. If, for example, a coatingcomposition is produced by using one or more components in aqueoussupply forms, the crucial factor in regard to characterization of thecomposition of the coating composition as a whole for the individualcomponents is how much particular active substance is present and notwhether certain components were used in water-free or water-containingform in the production of the coating composition. Accordingly, thepercentage of component C), i.e. water, is always the total of the waterpresent in the coating composition as a whole.

It is specifically pointed out that components A), B) and D) may be usedas individual species or as mixtures of such species. Accordingly, bothone and also several epoxy resins A), (meth)acrylates B) and solvents D)may be used.

In one embodiment, the solubility of component B) in water is less than0.1 g/l.

The coating compositions according to the invention are curablecompositions. Curing may be carried out by any of the methods known tothe relevant expert. In particular, radiation curing (for example UVcuring) may be used by virtue of the content in the compositionsaccording to the invention of component B) which contains C═C doublebonds. It may also be desirable to use typical epoxy resin hardeners. Inone embodiment, radiation curing is combined with curing by addition ofan epoxy resin hardener.

Coating Process

The present invention also relates to a process for the production ofcoatings, characterized in that a composition consisting of

-   A) 0.5 to 90% by weight epoxy resins excluding self-dispersing epoxy    resins,-   B) 0.5 to 90% by weight (meth)acrylates of a polyol,-   C) 5.0 to 98.0% by weight water,-   D) 0 or 0.1 to 3% by weight organic solvent and-   X) 0.5 to 10% by weight one or more dispersants,    with the following provisos:    -   the (meth)acrylates B) contain at least 2 reactive (meth)acrylic        groups per molecule,    -   the sum of the percentages by weight of components A), B),        C), D) and X) is 100% by weight and    -   the Brookfield viscosity of the composition (as measured at 23°        C.) is less than 15,000 mPas        is contacted with-   E) 1 to 200% by weight water-dilutable hardeners—% by weight    hardeners based on the epoxy resins A) and-   F) 0 to 90% by weight other additives and/or processing aids—% by    weight component F) based on the total quantity of all components,    and the resulting mixture is brought into the required shape and    allowed to cure.    Hardeners for the Process According to the Invention

Water-dilutable hardeners are used as component E) in the processaccording to the invention. In principle, the hardener may be selectedfrom any of the epoxy resin hardeners known to the relevant expert.Examples of suitable epoxy resin hardeners are functional aminecompounds, functional phenolic resins, functional mercaptans, functionalanhydrides or carboxylic acids which contain at least one functionalgroup, but preferably several such groups. The compounds suitable asepoxy resin hardeners mentioned here are known to the expert.

Polyfunctional amine compounds which allow curing at moderatetemperatures are preferably used as component E) in the processaccording to the invention. Examples of suitable compounds of this classare mentioned in WO 00/04106 cited at the beginning (cf. page 3, line 10to page 4, line 12). The compounds mentioned there are expresslyincluded in the disclosure of the present invention.

In one embodiment, compounds derived from adducts based onα,β-unsaturated carboxylic acid esters and mono-, di- orpolyaminopolyalkylene oxide compounds are used as component E). Moreparticularly, the compounds E) are selected from the group of types E1)to E3) described hereinafter.

Hardeners of the E1) type are obtainable by

-   (a) reacting one or more α,β-unsaturated carboxylic acid esters (I)    R²R³C═C(R⁴)COOR¹  (I)-    where R¹ is an aromatic or aliphatic radical containing up to 15    carbon atoms, the substituents R², R³ and R⁴ independently of one    another represent hydrogen, branched or unbranched, aliphatic or    aromatic groups containing up to 20 carbon atoms or a group    —(CH₂)_(n)—COOR¹, where R¹ is as defined above and n is a number of    0 to 10, in the presence of a transesterification catalyst with-   (b) one or more hydroxy compounds, compounds (a) and (b) being used    in such quantities that the equivalent ratio of the hydroxyl groups    in (b) to the ester groups COOR¹ in the α,β-unsaturated carboxylic    acid esters (a) is in the range from 1.5:1 to 10:1,    reacting the intermediate product Z1 obtained with-   (c) one or more mono-, di- or polyaminopolyalkylene oxide compounds,    an equivalent ratio of the reactive hydrogen atoms at the    aminonitrogen atoms of (c) to the ester groups in the intermediate    compound Z1 in the range from 10:1 to 1:10 being adjusted,    subsequently reacting the intermediate product Z2 obtained with-   (d) one or more polyepoxides, the equivalent ratio of oxirane rings    in polyepoxide (d) to reactive hydrogen atoms of the mono-, di- or    polyaminopolyalkylene oxide compounds used in (c) being adjusted to    a value of 100:1 to 1.5:1,    and subsequently reacting the intermediate product Z3 obtained with-   (e) one or more primary and/or secondary amines, the equivalent    ratio of oxirane rings in the intermediate product Z3 to the    reactive H atoms at the aminonitrogen atoms of (e) being adjusted to    a value of 1:1.5to 1:20.

The hardeners to be used in accordance with the invention are eitherliquid or solid substances, depending on their molecular weight.

The expression “equivalent ratio” is familiar to the expert. The basicconcept behind the notion of the equivalent is that, for every substanceparticipating in a reaction, the reactive groups involved in the desiredreaction are taken into consideration. By indicating an equivalentratio, it is possible to express the ratio which all the variousreactive groups of the compounds (x) and (y) used bear to one another.It is important in this connection to bear in mind that a reactive groupis understood to be the smallest possible reactive group, i.e. thenotion of the reactive group is not identical with the notion of thefunctional group. In the case of H-acid compounds, this means forexample that, although OH groups or NH groups represent such reactivegroups, NH₂ groups with two reactive H atoms positioned at the samenitrogen atom do not. In their case, the two hydrogen atoms within thefunctional group NH₂ are appropriately regarded as reactive groups sothat the functional group NH₂ contains two reactive groups, namely thehydrogen atoms.

In one embodiment, the intermediate compound Z1 and the compound (c) areused in such quantities that the equivalent ratio of reactive hydrogenatoms at the aminonitrogen atoms of (c) to the ester groups in theintermediate compound Z1 is in the range from 4:1 to 1:4 and moreparticularly in the range from 2.5:1 to 1.5:1.

In another embodiment, the equivalent ratio of oxirane rings in thepolyepoxide (d) to reactive hydrogen atoms of the mono-, di- orpolyaminopolyalkylene oxide compounds used in (c) is adjusted to a valuein the range from 50:1 to 10:1.

Examples of the α,β-unsaturated carboxylic acid esters (a) correspondingto formula (I) to be used in accordance with the invention are methylacrylate, ethyl acrylate, dimethyl maleate, diethyl maleate, dimethylfumarate, diethyl fumarate, dimethyl itaconate, diethyl itaconate.Particularly preferred compounds (a) are dialkyl maleates, moreparticularly diethyl maleate and dimethyl maleate.

The hydroxy compounds (b) may be aliphatic or aromatic. The compounds(b) should be inert to transesterification catalysts.

Examples of suitable aromatic compounds (b) are resorcinol,hydroquinone, 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), isomermixtures of dihydroxydiphenyl methane (bisphenol F), tetrabromobisphenolA, 4,4′-dihydroxydiphenyl cyclohexane,4,4′-dihydroxy-3,3-dimethyldiphenyl propane, 4,4′-dihydroxydiphenyl,4,4′-dihydroxybenzophenol, bis-(4-hydroxyphenyl)-1,1-ethane,bis-(4-hydroxyphenyl)-1,1-isobutane, bis-(4-hydroxyphenyl)-methane,bis-(4-hydroxyphenyl)-ether, bis-(4-hydroxyphenyl)-sulfone etc. and thechlorination and bromination products of the above-mentioned compounds.Bisphenol A is the preferred aromatic compound (b).

In one preferred embodiment, the hydroxy compounds (b) are selected fromthe class of fatty alcohols, alkanediols and polyetherdiols. If desired,these compounds may also be alkoxylated.

The fatty alcohols are primary alcohols containing 6 to 36 carbon atomswhich may be saturated or olefinically unsaturated. Examples of suitablefatty alcohols are hexanol, heptanol, octanol, pelargonyl alcohol,decanol, undecanol, lauryl alcohol, tridecanol, myristyl alcohol,pentadecanol, palmityl alcohol, heptadecanol, stearyl alcohol,nonadecanol, arachidyl alcohol, heneicosanol, behenyl alcohol,tricosanol, lignoceryl alcohol, 10-undecanol, oleyl alcohol, elaidylalcohol, ricinolyl alcohol, linoleyl alcohol, linolenyl alcohol,gadoleyl alcohol, arachidonyl alcohol, erucyl alcohol, brassidylalcohol.

The alkanediols are compounds corresponding to the general formulaHOCH₂—R⁵—CH₂OH, where R⁵ is a hydrophobic hydrocarbon radical which maybe saturated or unsaturated, linear or branched and may also containaromatic structural elements. Examples are hexane-1,6-diol,heptane-1,7-diol and octane-1,8-diol, polyoxytetramethylenediols—alsoknown as polytetrahydrofurans—and the so-called dimerdiols. Dimer diolsare most particularly preferred for the purposes of the presentinvention.

Dimerdiols are well-known commercially available compounds which areobtained, for example, by reduction of dimer fatty acid esters. Thedimer fatty acids on which these dimer fatty acid esters are based arecarboxylic acids which may be obtained by oligomerization of unsaturatedcarboxylic acids, generally fatty acids, such as oleic acid, linoleicacid, erucic acid and the like. The oligomerization is normally carriedout at elevated temperature in the presence of a catalyst, for exampleof clay. The substances obtained—dimer fatty acids of technicalquality—are mixtures in which the dimerization products predominate.However, small amounts of higher oligomers, more particularly the trimerfatty acids, are also present. Dimer fatty acids are commerciallyavailable products and are marketed in various compositions andqualities. Abundant literature is available on the subject of dimerfatty acids, cf. for example the following articles: Fette & Öle 26(1994), pages 47–51; Speciality Chemicals 1984 (May Number), pages 17,18, 22–24. Dimerdiols are well-known among experts, cf. for example amore recent article in which inter alia the production, structure andchemistry of the dimerdiols are discussed: Fat Sci. Technol. 95 (1993),No. 3, pages 91–94. According to the invention, preferred dimerdiols arethose which have a dimer content of at least 50% and more particularly75% and in which the number of carbon atoms per dimer molecule is mainlyin the range from 36 to 44.

Polyetherdiols in the context of the present invention are diolscorresponding to the general formula HOCH₂—R⁶—CH₂OH, where R⁶ is ahydrophobic hydrocarbon radical which may be saturated or unsaturated,linear or branched and may also contain aromatic structural elements andin which one or more CH₂ units must each be replaced by an oxygen atom.

A particularly attractive class of polyetherdiols can be obtained byalkoxylation of alkanediols, such as ethane-1,2-diol, propane-1,3-diol,propane-1,2-diol, butane-1,4-diol, butane-1,3-diol, pentane-1,5-diol,hexane-1,6-diol, heptane-1,7-diol and octane-1,8-diol,polyoxytetramethylenediols (polytetrahydrofurans) and dimerdiols. Theproduction of these alkoxylated diols is normally carried out asfollows: in a first step, the required diol is contacted with ethyleneoxide and/or propylene oxide and the resulting mixture is reacted in thepresence of an alkaline catalyst at temperatures of 20 to 200° C.Addition products of ethylene oxide (EO) and/or propylene oxide (PO)onto the diol used are obtained in this way. The addition products aretherefore EO adducts or PO adducts or EO/PO adducts with the particulardiol; in the case of the EO/PO adducts, the addition of EO and PO maytake place statistically or blockwise.

Suitable transesterification catalysts for the reaction of the compounds(a) and (b) are any transesterification catalysts known to the expertfrom the prior art. Examples of suitable catalysts are sodium methylate,dibutyl tin diacetate, tetraisopropyl orthotitanate. If desired, thecatalysts may be deactivated after the transesterification although thisis not absolutely essential.

Suitable amino components (c) are mono-, di- or polyaminopolyalkyleneoxide compounds. By this is meant that these compounds contain, on theone hand, one two or more amino functions (NH or NH₂ functions) and, onthe other hand, alkylene oxide units. The alkylene oxide units are, inparticular, ethylene oxide, propylene oxide and butylene oxide, ethyleneoxide and propylene oxide being particularly preferred. The compounds(c) are substances at least partly soluble in water at 20° C.

The production of the compounds (c) is known from the prior art andcomprises the reaction of hydroxyfunctional compounds with alkyleneoxides and subsequent conversion of the resulting terminal hydroxylgroups into amino groups.

So far as the reaction of hydroxyfunctional compounds with alkyleneoxides is concerned, ethoxylation and propoxylation are of particularimportance. The following procedure is usually adopted: in a first step,the required hydroxyfunctional compounds are contacted with ethyleneoxide and/or propylene oxide and the resulting mixture is reacted in thepresence of an alkaline catalyst at temperatures in the range from 20 to200° C. Addition products of ethylene oxide (EO) and/or propylene oxide(PO) are obtained in this way. The addition products are preferably EOadducts or PO adducts or EO/PO adducts with the particularhydroxyfunctional compound. In the case of the EO/PO adducts, theaddition of EO and PO may be carried out statistically or blockwise.

In one embodiment, substances with the general formulaR⁸—O—R⁹—CH₂CH(R¹⁰)—NH₂ are used as the compounds (c). In this formula:

-   -   R⁸ is a monofunctional organic group containing 1 to 12 carbon        atoms which may be aliphatic, cycloaliphatic or aromatic,    -   R⁹ is a polyoxyalkylene group made up of 5 to 200        polyoxyalkylene units, more particularly EO and/or PO units,    -   R¹⁰ is hydrogen or an aliphatic radical containing up to 4        carbon atoms.

Particularly suitable representatives of the compounds (c) for thepurposes of the present invention are the “Jeffamines” known to theexpert which are commercially available substances. One example is“Jeffamine 2070” which, according to the manufacturer Texaco, isproduced by reacting methanol with ethylene oxide and propylene oxideand then converting the terminal hydroxyl groups of the intermediateproduct initially obtained into amine groups (cf. WO 96/20971, page 10,lines 12–15).

The compounds (c) preferably have average molecular weights (numberaverage Mn) of 148 to 5,000 and more particularly in the range from 400to 2,000.

The epoxy compounds (d) are polyepoxides containing on average at leasttwo epoxy groups per molecule. These epoxy compounds may be bothsaturated and unsaturated and aliphatic, cycloaliphatic, aromatic andheterocyclic and may also contain hydroxyl groups. They may also containsubstituents which do not cause any troublesome secondary reactionsunder the mixing and reaction conditions, for example alkyl or arylsubstituents, ether groups and the like. These epoxy compounds arepreferably polyglycidyl ethers based on polyhydric, preferably dihydric,alcohols, phenols, hydrogenation products of these phenols and/ornovolaks (reaction products of mono- or polyhydric phenols withaldehydes, more particularly formaldehyde, in the presence of acidiccatalysts). The epoxy equivalent weights of these epoxy compounds arepreferably between 160 and 500 and more preferably between 170 and 250.The epoxy equivalent weight of a substance is the quantity of thesubstance (in grams) which contains 1 mole of oxirane rings. Preferredpolyhydric phenols are the following compounds: resorcinol,hydroquinone, 2,2-bis-(4-hydroxyphenyl)-propane (bisphenol A), isomermixtures of dihydroxydiphenyl methane (bisphenol F), tetrabromobisphenolA, 4,4′-dihydroxydiphenyl cyclohexane,4,4′-dihydroxy-3,3-dimethyldiphenyl propane, 4,4′-dihydroxydiphenyl,4,4′-dihydroxybenzophenol, bis-(4-hydroxyphenyl)-1,1-ethane,bis-(4-hydroxyphenyl)-1,1-isobutane, bis-(4-hydroxyphenyl)-methane,bis-(4-hydroxyphenyl)-ether, bis-(4-hydroxyphenyl)-sulfone etc. and thechlorination and bromination products of the above-mentioned compounds.Bisphenol A is most particularly preferred.

Bisphenol A

The polyglycidyl ethers of polyhydric alcohols are also suitablecompounds (d). Examples of such polyhydric alcohols are ethylene glycol,diethylene glycol, triethylene glycol, 1,2-propylene glycol,polyoxypropylene glycols (n=1–20), 1,3-propylene glycol, 1,4-butyleneglycol, pentane-1,5-diol, hexane-1,6-diol, hexane-1,2,6-triol, glyceroland bis-(4-hydroxycyclohexyl)-2,2-propane.

Other suitable compounds (d) are polyglycidyl ethers of polycarboxylicacids obtained by reaction of epichlorohydrin or similar epoxy compoundswith an aliphatic, cycloaliphatic or aromatic polycarboxylic acid, suchas oxalic acid, succinic acid, adipic acid, glutaric acid, phthalicacid, terephthalic acid, hexahydrophthalic acid,2,6-naphthalenedicarboxylic acid and dimerized linolenic acid. Examplesare adipic acid diglycidyl ester, phthalic acid diglycidyl ester andhexahydrophthalic acid diglycidyl ester.

A comprehensive list of suitable epoxy compounds (d) can be found in:

-   -   A. M. Paquin, “Epoxidverbindungen und Epoxidharze”,        Springer-Verlag, Berlin 1958, Chapter V, pages 308 to 461 and    -   Lee, Neville “Handbook of Epoxy Resins” 1967, Chapter 2, pages        201 and 2–33.

Mixtures of several epoxy compounds (d) may also be used,

Amines (e) suitable for the purposes of the invention are primary and/orsecondary amines. Preferred amines (e) are polyamines containing atleast two nitrogen atoms and at least two active aminohydrogen atoms permolecule. Aliphatic, aromatic, aliphatic-aromatic, cycloaliphatic andheterocyclic di- and polyamines may be used.

The following are examples of suitable amines (e): polyethylene amines(ethylene diamine, diethylene triamine, triethylene tetramine,tetraethylene pentamine, etc.), 1,2-propylene diamine, 1,3-propylenediamine, 1,4-butane diamine, 1,5-pentane diamine, 1,3-pentane diamine,1,6-hexane diamine, 3,3,5-trimethyl-1,6-hexanediamine,3,5,5-trimethyl-1,6-hexane diamine, 2-methyl-1,5-pentane diamine,bis-(3-aminopropyl)-amine, N,N′-bis-(3-aminopropyl)-1,2-ethane diamine,N-(3-aminopropyl)-1,2-ethane diamine, 1,2-diaminocyclohexane,1,3-diaminocyclohexane, 1,4-diaminocyclohexane, aminoethyl piperazines,the poly(alkylene oxide)diamines and triamines (such as, for example,Jeffamine D-230, Jeffamine D400, Jeffamine D-2000, Jeffamine D-4000,Jeffamine T403, Jeffamine EDR-148, Jeffamine EDR-192, Jeffamine C-346,Jeffamine ED-600, Jeffamine ED-900, Jeffamine ED-2001), meta-xylyenediamine, phenylene diamine, 4,4′-diaminodiphenyl methane, toluenediamine, isophorone diamine, 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 4,4′-diaminodicyclohexylmethane, 2,4′-diaminodicyclohexylmethane, the mixture of poly(cyclohexylaromatic)amines attached by amethylene bridge (also known as MBPCAA) and polyaminoamides.

Other suitable compounds (e) are the reaction products of the aminesjust mentioned with the above-described α,β-unsaturated carboxylic acidesters (a) and the reaction products of the amines just mentioned withthe above-described polyepoxy compounds (d).

Hardeners of the E2) type are obtainable by

-   (a) reacting one or more α,β-unsaturated carboxylic acid esters (I):    R²R³C═C(R⁴)COOR¹  (I)-    where R¹ is an aromatic or aliphatic radical containing up to 15    carbon atoms, the substituents R², R³ and R⁴ independently of one    another represent hydrogen, branched or unbranched, aliphatic or    aromatic groups containing up to 20 carbon atoms or a group    —(CH₂)_(n)—COOR¹, where R¹ is as defined above and n is a number of    0 to 10, with-   (c) one or more mono-, di- or polyaminopolyalkylene oxide compounds,    compounds (a) and (c) being used in such quantities that the    equivalent ratio of the reactive hydrogen atoms at the aminonitrogen    atoms of (c) to the C═C double bond in the α,β-position to the group    COOR¹ shown in formula (I) in the carboxylic acid esters (a) is in    the range from 10:1 to 1:10,    subsequently reacting the intermediate product Z4 obtained with-   (d) one or more polyepoxides, the equivalent ratio of oxirane rings    in polyepoxide (d) to reactive hydrogen atoms in the mono-, di- or    polyaminopolyalkylene oxide compounds (c) being adjusted to a value    of 100:1 to 1.5:1,    and subsequently reacting the intermediate product Z5 obtained with-   (e) one or more primary and/or secondary amines, the equivalent    ratio of oxirane rings in the intermediate product Z5 to the    reactive H atoms at the aminonitrogen atoms of (e) being adjusted to    a value of 1:1.5 to 1:20.

The foregoing observations on hardeners of the E1) type otherwise applyto the substances (a) and to the substances (c) to (e).

Hardeners of the E3) type are obtainable by

-   (a) reacting one or more α,β-unsaturated carboxylic acid esters (I):    R²R³C═C(R⁴)COOR¹  (I)-    where R¹ is an aromatic or aliphatic radical containing up to 15    carbon atoms, the substituents R², R³ and R⁴ independently of one    another represent hydrogen, branched or unbranched, aliphatic or    aromatic groups containing up to 20 carbon atoms or a group    —(CH₂)_(n)—COOR¹, where R¹ is as defined above and n is a number of    0 to 10, with-   (c) one or more mono-, di- or polyaminopolyalkylene oxide compounds,    compounds (a) and (c) being used in such quantities that the    equivalent ratio of the reactive hydrogen atoms at the aminonitrogen    atoms of (c) to the C═C double bond in the α,β-position to the group    COOR¹ shown in formula (I) in the carboxylic acid esters (a) is in    the range from 10:1 to 1:10,    subsequently reacting the intermediate product Z4 obtained with-   (g) one or more polyhydroxy compounds, the equivalent ratio of ester    groups in the intermediate compound Z4 to hydroxy groups in the    polyhydroxy compound (g) being adjusted to a value of 1:1.1 to 1:10,    and subsequently reacting the intermediate product Z6 obtained with-   (d) one or more polyepoxides, the equivalent ratio of oxirane rings    in polyepoxide (d) to hydroxyl groups in the intermediate product Z6    being adjusted to a value of 1.5:1 to 6:1,    and subsequently reacting the intermediate product Z7 obtained with-   (e) one or more primary and/or secondary amines, the equivalent    ratio of oxirane rings in the intermediate product Z7 to the    reactive H atoms at the aminonitrogen atoms of (e) being adjusted to    a value of 1:1.5 to 1:20.

The foregoing observations on hardeners of the E1) type otherwise applyto the substances (a) and to the substances (c) to (e).

The polyhydroxy compounds (g) may be aliphatic or aromatic. In oneembodiment, the polyhydroxy compounds (g) are selected from the class ofspecial aliphatic diols, namely alkanediols, especially dimer diols,polyether diols and polyester diols. The foregoing observations onhardeners of the E1) type in relation to component (b) apply to thealkanediols, including the dimerdiols, and the polyether diols.Polyesterdiols in the context of the invention are diols correspondingto the general formula HOCH₂—R⁷—CH₂OH, where R⁷ is a hydrophobichydrocarbon radical which may be saturated or unsaturated, linear orbranched and may also contain aromatic structural elements and in whichone or more CH₂ units must each be replaced by a COO unit. They arenormally produced by reacting difunctional polyols with dicarboxylicacids or anhydrides thereof. Commonly used polyols are ethylene glycol,propane-1,2-diol, butane-1,4-diol, hexane-1,6-diol. Typical dicarboxylicacids are succinic acid, adipic acid, phthalic anhydride.Hexane-1,6-diol adipic acid polyesters are particularly preferred.

In addition, so-called polyetheramines E4) may be used as hardeners E).These compounds are referred to hereinafter as type E4) hardeners. Thepolyetheramines (PEA) used for the purposes of the invention arediamino- or polyamino-polyalkylene oxide compounds. By this is meantthat these compounds contain on the one hand two or more amino functions(NH or NH₂ functions) and, on the other hand, alkylene oxide units. Thealkylene oxide units are in particular ethylene oxide, propylene oxideand butylene oxide, ethylene oxide and propylene oxide beingparticularly preferred.

The production of polyetheramines is known from the prior art andincludes the reaction of compounds containing hydroxyl groups withalkylene oxides and subsequent conversion of the resulting terminalhydroxyl groups into amino groups. WO-A-97/03108 (cf. page 8, lines13–19) cites corresponding prior art and states that polyetheramines arenormally obtained by amination of polyethers with ammonia in thepresence of catalysts, such as Ni/Cu/Cr for example.

So far as the reaction of compounds containing hydroxyl groups withalkylene oxides is concerned, ethoxylation and propoxylation are ofparticular importance. The procedure adopted is normally as follows: Ina first step, the desired hydroxyl-containing compounds are contactedwith ethylene oxide and/or propylene oxide and the resulting mixture isreacted in the presence of a catalyst at temperatures in the range from20 to 200° C. Addition products of ethylene oxide (EO) and/or propyleneoxide (PO) are obtained in this way. The addition products arepreferably EO adducts or PO adducts or EO-PO adducts with the particularhydroxyl-containing compound. In the case of the EO-PO adducts, theaddition of EO and PO may be carried out statistically or blockwise.

Suitable polyether blocks of the polyetheramines are, for example,polyethylene glycols, polypropylene glycols, copolymers of, for example,polyethylene glycols and polypropylene glycols,poly(1,2-butylene)glycols, poly(tetramethylene)glycols.

Particularly preferred polyetheramines E4) are diamines and triamines.“Diamines and triamines” are understood to be polyetheramines containingtwo or three terminal NH₂ groups per molecule. The diamines andtriamines described in EP-B-634 424 and WO-A-97/03108 are mostparticularly preferred. The disclosures of these two documents in regardto the structure of these diamines and triamines are hereby expresslyincluded in the teaching of the present invention. Reference is made inparticular to the following passages:

-   -   in the case of EP-B-634 424: page 6, line 23 to page 7, line 36.    -   in the case of WO-A-97/03108: page 29, line 1 to page 31, last        line.

According to the invention, particularly suitable diamines and triamines(of the PEA type) are those which are commercially obtainable fromHunstman Petrochemical Corporation under the name of “Jeffamine”. Thefollowing types are particularly preferred for the purposes of theinvention:

-   -   Jeffamine D-400    -   Jeffamine D-2000    -   Jeffamine D-4000    -   Jeffamine ED-600    -   Jeffamine ED-900    -   Jeffamine ED-2001    -   Jeffamine ED4000    -   Jeffamine ED-6000    -   Jeffamine T-3000    -   Jeffamine T-5000    -   Jeffamine ET-3000        These Jeffamine types may be used individually or in the form of        mixtures with one another.

The polyetheramines E4) preferably have average molecular weights(number average; Mn) of 400 to 12,000 and more particularly in the rangefrom 400 to 6,000.

Other suitable polyetheramines E4) are the commercially available“Pluronic” types known to the expert (manufacturer: BASF) and the “PCAmines” (manufacturer: Nitroil).

Additives and Processing Aids

Additives and/or processing aids known to the relevant expert may beadded as component F) in the course of the process according to theinvention. Examples include pigments, cement, gravel, deaerators,defoamers, dispersion aids, antisedimenting agents, accelerators, freeamines, flow control additives, conductivity improvers. The followingadditives and/or processing aids are of particular interest:

-   -   fillers (component F1),    -   open time extenders (component F2),    -   rheology additives (component F3).

The function of fillers F1) is to reduce the cost of the basicformulation, to obtain special surface effects and to control therheology of a system.

The combination of fillers has a critical effect on the storagestability and resistance of the final coating to chemicals. Calciumcarbonates as fillers do of course show a relatively poor resistance toacidic chemicals. Sand—an important filler for obtaining the necessarylayer thicknesses—is unsuitable for use as a sole filler on account ofits coarse particle structure by comparison with conventional fillers.Combination with other inert additives only reduces this behavior to asmall extent, but cannot compensate for the poor sedimentation behaviorif good application properties are to be retained. However, the use ofthe fillers is indispensable for obtaining special surface effects. Thedegree of gloss and the cost of a coating and also its resistance tochemicals as mentioned above are dependent factors which are tied to theuse of the correct combination of fillers.

The fillers used differ in their chemical character. For example, bariumsulfates, silica flours, aluminium silicates, natural or syntheticcalcium carbonates, silicates, calcium sulfate, talcum, kaolin, mica,feldspar, metals and metal oxides, aluminium hydroxide, carbon black,graphite and other fillers known to the expert may be used.

Suitable fillers have a specific gravity of 2 to 3 g/cm³ and preferably2.4 to 2.7 g/cm³ and a bulk density of, in particular, 0.6 to 1.0 g/cm³.

To avoid sedimenting problems and to establish the important processingviscosity, fillers with particle size distributions of 0 to 100 μm andpreferably 0 to 50 μm are particularly appropriate. The particle sizedistribution is a distribution function of the particle size and isdetermined by particle size analysis and illustrated as a particle sizedistribution curve (for example particle size distribution curve to DIN66165-1: 1097-04).

The following combinations are most particularly suitable as componentF1): silica sand/Minex S 20, silica sand/Schwerspat (heavy spar) C 14 orsilica sand/Calcicoll W 7. The substances mentioned here arecommercially obtainable.

In one embodiment, component F1) is used in a quantity of 20 to 60% byweight.

Wax-based open-time extenders F2). Systems such as these are known tothe expert (a definition of waxes can be found, for example, in U.Zorll, Ed., RÖMPP—Lexikon, Lacke und Druckfarben, p. 615, Georg ThiemeVerl., Stuttgart, New York, 1998). Waxes in the form of aqueousemulsions or in solid supply forms on mineral support materials are usedduring processing to extend the open time and to increase theflexibility and plasticity of the filling and insulating compounds. Theexpression “waxes” encompasses both waxes in the narrower sense andfatty alcohols.

Corresponding wax-based processing additives are described in detail inR. Neumann, H.-G. Schulte, R. Höfer, Pulver, das Eigenschaften schafft,Bautenschutz und Bausanierung, Heft 3/1999, pp/22–27 and in U. Nagorny,Extension of workability of synthetic resin plasters with additivesbased on fatty raw materials; ConChem-Journal, No. 1/1994, pp. 23–26).Powder-form wax-based open-time extenders, more particularly fattyalcohols containing 16 to 72 carbon atoms per molecule on a solidsupport, are particularly suitable. In this connection, reference isspecifically made to the disclosure of WO 98/49114. Particularlysuitable wax-based open-time extenders are the products Loxanol® 842 DP(aqueous dispersion) and Loxanol® P (water-free powder-form solid)marketed by Cognis Deutschland GmbH, Düssledorf/DE.

In one embodiment, component F2) is used in a quantity of 0.1 to 2.0% byweight.

Rheology additives F3). Any rheology additives known to the expert,preferably layer silicates or poly (meth)acrylates or cellulose ethersor so-called associative thickeners, may be used individually or incombination.

Layer silicates in combination with hydrophobically modified polyetherurethanes (HEURs) or hydrophobically modified polyethers (HMPEs) arepreferably used. Hydrophobically modified means that hydrophobic groupsare present in the molecules of the classes of compounds mentioned.Particularly preferred HEURs are the solventless HEURs described in G.Schulte, J. Schmitz and R. Höfer, Additive für wäβrige Systeme undumweltfreudliche Lacke, Welt der Farben, 28–31 (12/1997) and thepseudoplastic HEURs described in DE-A-42 42 687.

In one embodiment, component F3) is used in a quantity of 0.1 to 3.0% byweight.

Use

The present invention also relates to the use of compositions consistingof

-   A) 0.5 to 90% by weight epoxy resins excluding self-dispersing epoxy    resins,-   B) 0.5 to 90% by weight (meth)acrylates of a polyol,-   C) 5.0 to 98.0% by weight water,-   D) 0 or 0.1 to 3% by weight organic solvent and-   X) 0.5 to 10% by weight one or more dispersants,    with the following provisos:    -   the (meth)acrylates B) contain at least 2 reactive (meth)acrylic        groups per molecule,    -   the sum of the percentages by weight of components A), B),        C), D) and X) is 100% by weight and    -   the Brookfield viscosity of the composition (as measured at 23°        C.) is less than 15,000 mPas        for the production of coatings.

The present invention also relates to the use of the above-describedcoating compositions as levelling and insulating compounds, moreparticularly in the building industry. The use of the coatingcompositions for floors is particularly preferred.

EXAMPLES

Substances Used

-   Chem-Res E 30: liquid epoxy resin based on bisphenol A/F (Cognis    Deutschland GmbH)-   Photomer 4006: trimethylol propane triacrylate (manufacturer: Cognis    Deutschland GmbH)-   Photomer 4094: triacrylate of the reaction product of 1 mol glycerol    with 3 mols propylene oxide (manufacturer: Cognis Deutschland GmbH)-   Disponil 23: commercially available dispersant (manufacturer: Cognis    Deutschland GmbH)-   Waterpoxy 751: epoxy resin hardener (manufacturer: Cognis    Deutschland GmbH)    Water-based Coating Compositions

Example 1 Invention

The following composition was prepared by combining and stirring theindividual components:

-   -   60 parts by weight Chem Res E 30    -   10.4 parts by weight Photomer 4006    -   40 parts by weight water    -   2 parts by weight Disponil 23

Example 2 Invention

As Example 1 except that Photomer 4094 was used instead of Photomer 4006(same quantity by weight).

Application Examples

Example 3 Invention

71.2 parts by weight Waterpoxy 751 were added to the composition ofExample 1. The mixture was applied to a metal substrate in a layerthickness of 30 μm and left to cure.

Example 4 Invention

71.2 parts by weight Waterpoxy 751 were added to the composition ofExample 2. The mixture was applied to a metal substrate in a layerthickness of 30 μm and left to cure.

Example 5 Comparison

The following composition was prepared by combining and stirring theindividual components:

-   -   60 parts by weight Chem Res E 30    -   40 parts by weight water    -   2 parts by weight Disponil 23

71.2 parts by weight Waterpoxy 751 were added to this composition. Themixture was applied to a metal substrate in a layer thickness of 30 μmand left to cure.

The gel time as defined in DIN 16945 was determnined as a measure of theprocessing time of the compositions of Examples 3 and 4 and ComparisonExample 5. The results obtained are set out in Table 1.

TABLE 1 Example Gel time to DIN 16945 [mins.] Example 3 (invention) 2Example 4 (invention) 10 Example 5 (invention) 300

1. A water-based coating composition consisting of: (a) from 0.5 to 90%by weight of at least one epoxy resin other than self-dispersing epoxyresin; (b) from 0.5 to 90% by weight of at least one (meth)acrylate of apolyol; (c) from 5.0 to 98.0% by weight of water; and (d) from 0.5 to10% by weight of one or more dispersants; wherein the at least one(meth)acrylate comprises at least two (meth)acrylate groups permolecule, and wherein the Brookfield viscosity of the composition isless than 15000 mPas.
 2. The composition according to claim 1, whereinthe solubility of the at least one (meth)acrylate of a polyol in wateris less than 0.1 g/l.
 3. The composition according to claim 1, whereinthe at least one epoxy resin is present in an amount of from 5 to 50% byweight.
 4. The composition according to claim 1, wherein the at leastone epoxy resin is present in an amount of from 20 to 50% by weight. 5.The composition according to claim 1, wherein the water is present in anamount of from 10 to 50% by weight.
 6. The composition according toclaim 1, wherein the water is present in an amount of from 35 to 50% byweight.
 7. The composition according to claim 1, wherein the at leastone (meth)acrylate of a polyol comprises trimethylol propanetriacrylate.
 8. The composition according to claim 1, wherein the one ormore dispersants comprises a surfactant selected form the groupconsisting of anionic and nonionic surfactants.
 9. A water-based coatingcomposition consisting of: (a) from 0.5 to 90% by weight of at least oneepoxy resin other than self-dispersing epoxy resins; (b) from 0.5 to 90%by weight of at least one (meth)acrylate of a polyol; (c) from 5.0 to98.0% by weight of water; (d) from 0.5 to 10% by weight of one or moredispersants; and (e) from 0.1 to 3% by weight of an organic solvent;wherein the at least one (meth)acrylate comprises at least two(meth)acrylate groups per molecule; and wherein the Brookfield viscosityof the composition is less than 15,000 mPas.
 10. A method for preparinga cured coating composition, said method comprising: (A) providing acoating composition consisting of: (a) from 0.5 to 90% by weight of atleast one epoxy resin other than self-dispersing epoxy resins; (b) from0.5 to 90% by weight of at least one (meth)acrylate of a polyol; (c)from 5.0 to 98.0% by weight of water; and (d) from 0.5 to 10% by weightof one or more dispersants; wherein the at least one (meth)acrylatecomprises at least two (meth)acrylate groups per molecule; and whereinthe Brookfield viscosity of the composition is less than 15,000 mPas;(B) contacting the composition with from 1 to 200% by weight, based onthe at least one epoxy resin, of a water-dilutable hardener; and (C)allowing the composition and hardener to cure.
 11. The method accordingto claim 10, wherein the solubility of the at least one (meth)acrylateof a polyol in water is less than b 0.1 g/l.
 12. The method according toclaim 10, wherein the at least one epoxy resin is present in an amountof from 5 to 50% by weight.
 13. The method according to claim 10,wherein the at least one epoxy resin is present in an amount of from 20to 50% by weight.
 14. The method according to claim 10, wherein thewater is present in an amount of from 10 to 50% by weight.
 15. Themethod according to claim 10, wherein the water is present in an amountof from 35 to 50% by weight.
 16. The method according to claim 10,wherein the at least one (meth)acrylate of a polyol comprisestrimethylol propane triacrylate.
 17. The method according to claim 10,wherein the one or more dispersants comprises a surfactant selected fromthe group consisting of anionic and nonionic surfactants.
 18. A methodfor preparing a cured coating composition, said method comprising: (A)providing a coating composition consisting of: (a) from 0.5 to 90% byweight of at least one epoxy resin other than self-dispersing epoxyresins; (b) from 0.5 to 90% by weight of at least one (meth)acrylate ofa polyol; (c) from 5.0 to 98.0% by weight of water; (d) from 0.5 to 10%by weight of one or more dispersants; and (e) from 0.1 to 3% by weightof an organic solvent; wherein the at least one (meth)acrylate comprisesat least two (meth)acrylate groups per molecule; and wherein theBrookfield viscosity of the composition is less than 15,000 mPas; (B)contacting the composition with from 1 to 200% by weight, based on theat least one epoxy resin, of a water-dilutable hardener; and (C)allowing the composition and hardener to cure.